Now we know why the 49ers signed defensive tackle Chris Jones.
They needed someone to fill the roster spot of veteran lineman Cedric Thornton.
The team announced that Thornton was retiring after seven years in the NFL.
The 30-year-old Thornton signed with the 49ers just before the start of camp.
He was with the Bills last year, and also spent a year with the Cowboys. His first five seasons with the Eagles came after making the team as an undrafted free agent from Southern Arkansas.